Combined Spinal Epidural Anaesthesia with BiPAP-Three Case Reports

Summary We report three cases where BiPAP (bi-level positive airway pressure) was used with CSEA (combined spinal epidural anaesthesia) to over come the hypoventilation due to preoperative poor respiratory reserves and additive effect of sedation. Combination of BiPAP with spinal, epidural and CSEA have been used successfully in patients of severe COPD (chronic obstructive pulmonary disease) for various surgical procedures. This combination provides safe alternative to conventional general anaesthesia, as it avoids need for postoperative ventilatory support and its deleterious effects.


Introduction
Severe chronic obstructive pulmonary disease (COPD) cases for surgery carry high risk of perioperative morbidity and mortality due to poor respiratory reserve, and associated systemic diseases like hypertension, corpulmonale, CCF(congestive cardiac failure) etc. General anaesthesia if possible, is better avoided due to riskof impendingrespiratoryfailure and need for postoperative ventilatory support. 1,2 Spinal and epidural anaesthesia provides safe and effective anaesthesia in such high risk patients. 3 But problem of intraoperativesedation remainunsolved assedation may cause hypoxia especially in anxious patients who want to be unconscious and, for laparoscopic procedures where sedation is required to avoid the discomfort of CO2 insufflation.Upper abdominaloperation requires adequate analgesia up to T4 which always compromise on respiratory muscle functions and when sedation is given in already respiratory compromised patients hypoxia is inevitable. However, this hypoxia can be prevented by using intraoperative BiPAP, as it supports the patient's own respiration without interfering airways and preventinghypoxia by maintaining functional residualcapacity(FRC). This concept recently has been used in compromised respiratory system pa-tients ofsevere COPDfor various surgical indications. 4,5 We report the use of a combination of combined spinalepidural anaesthesia (CSEA) and bilevel positive airway pressure(BiPAP) in three patients of severe COPD for inguinal hernia repair, laparoscopic cholecystectomy and radical hysterectomy.

Case-1
An 82-yr-male patient presented with obstructed right inguinalhernia. He was aknown caseof advanced COPD, cor-pulmonale and pulmonary artery hypertension. He had very poor respiratory reserve, he was confined to bed with oxygen support at most of the time of the day, and he was normally unable to lie flat. He had many episodes of CCF and hospitalization in intensive care. Echocardiography showed mild aortic regurgitation with decreased left ventricular function. ECG showed ST depression in inferior leads. Blood investigations and electrolyteswere normal.

Case-2
A 65-yr-female patient presented with gall stones and scheduled for laparoscopic cholecystectomy. She was confined to bed and was under treatment for paraplegia for 2 months, MRI showed compression at D7. She was a case of COPD, old pulmonary tuberculosis, NIDDM on oral hypoglycemic, ischemic heart disease with recurrent chest pain, ECG showed left bundle branch block(LBBB), old anteroseptal infarctionwith left axis deviation.Echocardiography showed thin and hypokinetic intraventricular septum, mild LV systolic dysfunction and 44% left ventricular ejection fraction. She had history of untoward cardio-respiratory event under generalanaesthesia andintensive care admission (details not available, procedure was abandoned) during Endoscopic Retrograde Cholangiopancreatography (ERCP) for common bile duct (CBD) stent, two weeks before in other hospital.

Patient-3
A 70 yr, 86 kg female patient (Fig 1) scheduled for radical hysterectomy. She was a known case of hypertension, diabetes mellitusand COPD and episodes of sleep apnea. She was obese, had difficult airways (MPS 4) and had history of difficulty inmaintaining airways undergeneralanaesthesia(midazolam +propofol+ sevoflurane) in last surgery for cervical biopsy 7 days before in our hospital which was managed with bag and maskoxygenation by two anaesthetists.

Anaesthesia technique
Informed consent for high risk was taken from patients,possible optimization of generalcondition (antibiotics, insulin, bronchodilators etc.) was done, and medicines were continued as indicated in preoperative period. In operation theatre standard monitoring was commenced, i.v. access established, and an i.v. infusion of normal saline solution started. Oxygen was administered through nasal prongs. Combined spinal epiduraltechniqueby needlethrough needle(CSE Cure, Portex Combined Spinal/Epiduralminipack27G/18G) was used for anaesthesia. Epidural catheter (18G) was insertedthrough Tuohy needle 3-4cm in epiduralspace and after negative aspiration test for blood and CSF 2mlsaline was used to flush the catheter to know the patency. Levelof block was decided by nature of operation and epidural top-up were given as required (Table-1). Sedation was given when patient requested for sleep or showedundue anxious and uncooperative behavior.Initially with0.5mg incrementsof midazolam and 10-20mg bolus of propofol and then infusion of propofolwas started @ 0.5mg/kg/hr. BiPAP (BiPAP®

Fig 1 Photograph of patient #3 with difficult airway (Mallampati class-4) (Consent for Photograph and publication taken)
Auto-M Series RESPIRONICS®) was started when SpO2 did not improve with oxygen by nasalprongs or Poly mask. In first two patients IPAP-14 and EPAP-5 adequately maintained oxygenation, in hysterectomy patient IPAP-20 was required when SpO2 did not improve above 87%. ABG was done after one hour of bronchoconstriction on extubation, all of these benefits have been reported in the use of combined spinal and epidural anaesthesiafor abdominalaortic aneurysm repair in patients with severe COPD. 5 We used combination of BiPAP(Bi-level positive airway pressure) and combined spinalepidural anaesthesia (CSEA) in our threehigh riskpatients scheduled for inguinalhernia repair,laparoscopic cholecystectomy and hysterectomy havingmultiple systemicdiseases including poor respiratory reserves due to severe COPD. CSEA is a better optionin high riskpatients because, it provides safe and effective neuraxial blockthan either spinal orepiduralalone. 7 BiPAPhelpedto maintain oxygenation (Table-2) when patients were sedated with propofoland were unable tomaintain oxygenation 8 with conventional methods e.g. nasalprong and Poly mask. General anaesthesiacould havebeen analternative with intubationand IPPVbut therewas likelihoodthat these patientswould needpostoperative ventilation and, generalanaesthesia it self hasdetrimental effectson postoperative respiratory functions. 3,6 Noninvasive ventilation and propofolsedation with spinal, epiduraland CSEA has beenusedandaccepted clinicallypracticable method in various surgical procedures and it helps to correct alveolar hypoventilation duringspinal anaesthesia, 4,5,8,9 There are complicationsassociated withthe useof noninvasive positive pressure ventilation (NIPPV)and these include localtrauma, gastricdistension, eyeirritation, sinus congestion, air leaks, and haemodynamic effects. 4 These problemswere managedwith protectiveeye pads BiPAP commencement (Table-2). BiPAP was gradually withdrawn (dependingup onpatients' acceptance) and oxygen was continued by Poly mask in postoperative period. Postoperative analgesia was provided with 6ml epidural injection of 0.125% bupivacaine+ buprenorphine 100 -300µg on demand basis.All three patients had uneventfulrecovery and discharged from the hospital.

Discussion
Spinaland epiduralanaesthesia are beneficial for both obese and advanced COPD patients. Compared with general anaesthesia, the maintenance of spontaneous breathing means there is less cephalad displacement of the diaphragm and less risk ofatelectasis, closing capacity and FRC are less affected and pulmonary gas exchange is better maintained. 3 However, sedation given in conjunction with a regionalblock decreases sensitivity to CO2and hypoxia, and thus these patients are unable to deal effectively with hypercarbia and hypoxia moreover,combined effectof pneumoperitoneum (as in laparoscopiccholecystectomy) and sedation can lead to h yp oventilation and arterial oxygen desaturation. 6 Superior postoperative analgesia without risking respiratory depression, and avoidance of the strong stimulation of intubation or the risk of  (laparoscopic cholecystectomy) showing BiPAP machine , oxygen source and protective eye pads (Fig 2), nasogastric tube (some time this interfere with airtight seal),extended neckposition andselectinglower BiPAP values (IPAP-14and 20, EPAP 5-6) and intravenous fluids.
The use of BiPAPfrom beginning of procedure and in a planed manner is ideal to avoid poor patient compliance. This is achieved by a controlled, gradual introduction, checkingthe patient's acceptance before performing the spinal, and then the use of targetcontrolled sedation during surgery. 4 We report the use of a combination of combined spinal epidural anaesthesia and BiPAP (bi-level positive airway pressure) in three patients of severe COPD whodeveloped hypoventilationwhen sedationwas given .This technique helpsin managinghigh riskCOPD patients with advanced lung disease who are at risk of hypoventilation due to sedation under regional anaesthesia.